Portable does not mean risk-free. Water, electricity, heat, vibration, lint, and renter rules all meet in a small area, so the safest setup is the one you can supervise and maintain.
Before every load
Inspect hoses, fittings, the drain route, cord, plug, and floor area. Make sure the appliance is level and stable. Keep the water source and drain visible enough to catch a leak or slipping hose early.
During washing and drying
Follow the manual, stay nearby, and stop if you notice leaking, unusual movement, heat, smell, or sound. Do not defeat grounding, use an unspecified extension cord, overload a circuit, or vent moist air indoors.
After the cycle
Shut off and disconnect water as directed, clean lint controls, empty any collection container, dry wet surfaces, and store hoses so residual water cannot damage the floor.
Protect the room
Use the appliance only on a surface allowed by the manufacturer and keep the unit level. Water alarms or suitable containment can provide an early warning, but they do not make an unsafe connection acceptable. Know where the water shutoff is and keep the drain visible during early loads so a developing problem is easier to catch.
Protect the tenancy
Review the lease, building rules, and insurance implications before bringing in the appliance. Ask for written clarification when the rules are unclear. Photograph the setup and keep manuals and receipts. Documentation cannot override a prohibition, but it creates a better record of what was approved and how the equipment was installed.